Option 020 15dB low noise PreAmplifier All V4 Models Significantly better sensitivity .Integrated. For this price a Must-Order! STRONGLY recommended!
(ONLY SPECTRAN® V4-Series). Integrated & switchable. Expands the measurement range up to 15dB.

This option provides an internal, super low-noise 15dB preamplifier, enabling maximum performance particularly when measuring extremely weak signals. It is switched via a TRUE RF switch. There really is no excuse for not ordering this one, considering its very attractive price!
The maximum sensitivity of the V4 series without option 020 is lower by 15dB.